1. Field of the Invention
The invention generally relates to temporary load supports. More particularly, the invention relates to removable supports used for providing access and supporting equipment, for example, in construction, repair and inspection of facilities involving poles, towers, masts, and like structures generally extending vertically.
2. Description of the Related Art
Temporary load supports are used in many applications where it is desirable to provide access to a person or to support equipment for a short time while specific tasks are accomplished. It is desirable that such supports be removed afterwards, for example to limit access to places which are dangerous, or to reduce the risk of tampering by others. An example of one such application is providing temporary load supports adjacent side surfaces of power poles. In such applications temporary load supports may act as hand and foot holds to support the weight of a person, and may be used to support lines and/or pulleys and the like to lift equipment, to name two possible functions. The invention will be discussed in terms of such supports suitable for use with power poles, light poles, masts, towers, and the like but this is for convenience only, as the invention is not limited to such applications.
Conventionally, when wooden poles are involved, metal temporary supports can be attached by driving or screwing them into the wood of the pole. Some prior systems involved a first element which was permanently attached to the wooden pole, and a second element which was attachable to the first element, but which could be attached and removed without undue effort. This is important as it is accomplished while a linesman or other worker is ascending or descending the pole, often carrying a heavy load of equipment and/or tools. The worker attaches the temporary supports ahead as the worker climbs the pole, and removes them from below as the worker descends. An example of such a prior system is illustrated in the accompanying drawings and described in more detail below.
When a metal pole is involved, such a two part system conventionally requires the pole to be drilled and tapped for each support location. The permanent part of the system is then bolted onto the pole. This process is time consuming, and therefore costly. Moreover, the process is often done in the field. Field installation further adds to the cost, and quality cannot be controlled as well as would be the case in shop fabrication and assembly processes.
Prior two part systems conventionally work by sliding a support member, the temporary part, configured as a footrest/handhold, over the head of a screw or bolt, the bolt being a permanent part attached to the pole. A slot is provided in the support member which receives the head of the screw or bolt. The bolt can be provided with flats, and/or a raised stop provided which is received in the slot so that the support member is inhibited from rotation. This is important as gravity is what holds the support member on the bolt in such conventional systems when the support member is unloaded. If the support member rotates sufficiently, it will be able to simply slide off. A disadvantage of this system is that a worker may inadvertently snag or otherwise push a support member upward and off the bolt. The support member can strike another worker, or a bystander, below, causing injury. Also, such supports are often spaced far enough apart that inadvertent loss of even one support makes reaching between supports difficult, and this materially increases the risk of a fall. The problem is particularly acute when the worker is loaded with heavy equipment.
It has been recognized that it is desirable to provide a system in which a temporary support member does not easily come off inadvertently, and which mitigates the need for the expensive operations for attachment of the system to the pole. The invention accordingly provides a temporary load support system configured for supporting a load from an object comprising: a) a stud incorporating a stem having proximal and distal ends, carried by the object, the proximal end adjacent the object, the stud being configured to transfer a load force to the object through the proximal end; b) a crosspiece incorporated in the stud so as to transfer a load force to the stud, the crosspiece extending laterally from the stud; and c) a support member having a proximal end and a distal end and defining a slot, the support member being configured for temporary attachment to the stud at the proximal end of the support member by slipping the support member over the stud and subsequently rotating the support member to provide a mechanical interlock between the support member and the stud and crosspiece, the slot being configured to receive the crosspiece upon rotation of the support member, such that a load force can be transferred from the support member to the stud, and thereby to the object.
In a more detailed aspect, the removable load support system can further comprise a rotation inhibition interlock. Moreover, the rotation inhibition interlock can be provided by the stud and the support member each further comprising a rotation inhibiting surface, and the rotation inhibiting surfaces of the stud and support member cooperating to inhibit rotation of the support member with respect to the stud after the respective rotation inhibiting surfaces are brought together.
In a further more detailed aspect, the stud can incorporate two flats, each flat comprising a rotation inhibiting surface. The support member can comprise two cooperating surfaces comprising rotation inhibiting surfaces which cooperate with the flats to provide the rotation inhibition interlock.
In another more detailed aspect, the stud can be attached to the object by an electric weld, and further, the weld can be accomplished by directing an electric current throughout the stud and the object to heat the stud and object where they are to be welded together, whereby rapid attachment of the stud is facilitated.
In a further more detailed aspect, the removable load support system can further comprise a flange adjacent the slot defined by the support member, the flange being configured to strengthen the support member adjacent the slot. Moreover, where the support member is formed of metal plate the flange can be formed by deformation of the metal plate adjacent the slot.
In another more detailed aspect, the removable load support system can include a rotation inhibition surface incorporated in the stud and a rotation inhibition surface incorporated in the support member, the rotation inhibition surfaces cooperating to inhibit relative rotation of the support member and the stud. The support member and stud can be configured such that the rotation inhibition surfaces are engaged cooperatively to prevent rotation by a translational movement of the support member with respect to the stud after the support member has been placed over the stud and rotated to a point where the translational movement is enabled to bring the support member into interlocking relation with the stud. The direction of translational movement can be made to be parallel to a direction in which a load force is applied to the support member.
In a further more detailed aspect, the support member can be formed of a metal plate bent in a downwards U-shape defining a top portion and downwardly depending sides. The support member can further comprise a bottom connection between the sides, configured to stabilize the bottom of the sides and resist deformation comprising spreading of the sides under load.
These and other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings.